Non-thyroid cancer incidence in Belarusian residents exposed to Chernobyl fallout in childhood and adolescence: Standardized Incidence Ratio analysis, 1997–2011

Abstract

Background While an increased risk of thyroid cancer from post-Chernobyl exposure to Iodine-131 (I-131) in children and adolescents has been well-documented, risks of other cancers or leukemia as a result of residence in radioactively contaminated areas remain uncertain. Methods We studied non-thyroid cancer incidence in a cohort of about 12,000 individuals from Belarus exposed under age of 18 years to Chernobyl fallout (median age at the time of Chernobyl accident of 7.9 years). During 15 years of follow-up from1997 through 2011, 54 incident cancers excluding thyroid were identified in the study cohort with 142,968 person-years at risk. We performed Standardized Incidence Ratio (SIR) analysis of all solid cancers excluding thyroid (n=42), of leukemia (n=6) and of lymphoma (n=6). Results We found no significant increase in the incidence of non-thyroid solid cancer (SIR=0.83, 95% Confidence Interval [CI]: 0.61; 1.11), lymphoma (SIR=0.66, 95% CI: 0.26; 1.33) or leukemia (SIR=1.78, 95% CI: 0.71; 3.61) in the study cohort as compared with the sex-, age- and calendar-time-specific national rates. These findings may in part reflect the relatively young age of study subjects (median attained age of 33.4years), and long latency for some radiation-related solid cancers. Conclusions We found no evidence of statistically significant increases in solid cancer, lymphoma and leukemia incidence 25 years after childhood exposure in the study cohort; however, it is important to continue follow-up non-thyroid cancers in individuals exposed to low-level radiation at radiosensitive ages.

Gilbert W. Beebe Symposium on 30 Years after the Chernobyl Accident: Current and Future Studies on Radiation Health Effects

“…(29–31)], and a case-control study which showed a significant association of leukemia risk with increasing radiation dose in Ukraine (but not in Belarus or Russia) could be due to sampling-derived bias (32). In the UkrAm and BelAm cohorts of children there have only been 11 cases of leukemia, suggesting a small but nonsignificant increase in risk (33, 34).…”

Health Effects of Reactor Accidents with Special Regards to Chernobyl

“…Nevertheless, there have been many post-Chernobyl studies of leukaemia and cancer morbidity in the populations of 'contaminated' areas in the three countries. In relation to the increase in the incidence of leukemia after irradiation in utero or during childhood, about ten ecological studies were carried out in three countries from 1993 to 2003, and the effect -2016, for example, [24][25][26] the results are contradictory. The same conclusion regarding non-thyroid cancer and breast cancer alone was made in.…”

“…The same conclusion regarding non-thyroid cancer and breast cancer alone was made in. 25,26) It is thought, however, that for most solid cancers, the minimum latent period is of the order of 10 radiological impact of the accident.…”